Control of invasive alien species in the project sites: progress report at the end of the first year - IdroLIFE
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Control of invasive alien species in the
project sites: progress report at the end of
the first year.
Codice Azione C.5.
Control of invasive alien species in the project sites: progress
Titolo
report at the end of the first year.
Codice Subazione -
Titolo -
Tipo di elaborato Deliverable
Stato di avanzamento Finale Version
Data 30.04.2018
Autori CNR – Istituto per lo Studio degli Ecosistemi
Responsabile dell’azione CNR – Istituto per lo Studio degli Ecosistemi
A B C D E F Control of invasive alien species in the project sites
LIFE Nature and Biodiversityproject
LIFE15 NAT/IT/000823
Project title: Conservation and management of freshwater fauna of EU
interest within the ecological corridors of Verbano-Cusio-Ossola
Project acronym: IdroLIFE
Name of the Member State: IT - Italy
Start date: 15-11-2016
End date: 14-11-2020
Coordinating beneficiary CNR - Institute of Ecosystem Study (abbrev. CNR-ISE)
Associated beneficiaries Provincia del Verbano-Cusio-Ossola (PROVCO)
Ente Parco Nazionale della Val Grande (PNGV)
G.R.A.I.A. srl - Gestione e Ricerca Ambientale Ittica Acque (GRAIA)
Action C5
Action Title Control of invasive alien species in the project sites
Subaction -
Subaction Title -
Title of the product Progress report at the end of the first year
Type of product Deliverable
Progress Final version
Date 14.05.2018
Authors Silvia Zaupa, Paolo Sala, Mattia Iaia, Pietro Volta
Beneficiary responsible for
CNR – Istituto per lo Studio degli Ecosistemi
implementation
Expected end date 28.02.2018
Indice
Sommario
2 INTRODUCTION ......................................................................................................................................... 4
3 sites ........................................................................................................................................................... 5
3.1 SPA IT1140013 Lago di Mergozzo and Mont’Orfano .................................................................... 5
3.2 SCI IT1140001 Fondo Toce ............................................................................................................. 6
3.3 SPA IT1140017 Fiume Toce ............................................................................................................ 7
4 EXECUTION ................................................................................................................................................ 8
5 RESULTS.................................................................................................................................................... 9
6 NEXT STEPS ............................................................................................................................................ 13
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3
1 INTRODUCTION
This action is dedicated to control the spread of alien invasive species in the project sites.
As reported in the project proposal, the targeted species (Fig. 1) of this action in the SPA Lago di
Mergozzo and Montorfano, and in the adjacent SCI Fondo Toce, are the welsh catfish Silurus glanis (Fig.
1A), the ruffe Gymnocephalus cernuus (Fig. 1B), the black bullhead Ameiurus melas (Fig. 1C), the
pumpkinseed Lepomis gibbosus (Fig. 1D) and the crucian carp Carassius carassius (Fig. 1E) among
fishes. Target species among crayfish are the non-native Red Swamp crayfish Procambarus clarkii (Fig.
1F) and the Spynicheek crayfish Orconectes limosus (Fig. 1G).
In the SPA Toce River the targeted species of this action is mainly the brown trout Salmo trutta (Fig. 1H)
of atlantic aplotype (phenotypically characterized by large and few red and black spots, absence of
marbled body) and the rainbow trout Oncorhynchus mykiss (Fig. 1I).
A) B) C)
D) E) F)
G) H) I)
Fig. 1 – Targeted alien species
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4
2 SITES
2.1 SPA IT1140013 Lago di Mergozzo and Mont’Orfano
The Mergozzo Lake (about 1.8 km2, max depth 74 m) (Fig. 2) is an oligotrophic lake under strong
touristic flow related to water sports and fishing, particularly during the late spring and summer season.
The site is extremely important for the presence of native fish fauna such as Rutilus pigus,
Chondrostoma soetta, Cottus gobio, Alosa agone and Salmo marmoratus. Among the main threats now
present, the most relevant is the presence of alien species such as the black bullhead Ameiurus melas
and the ruffe Gymnocephalus cernuus. The human pressure along to the shoreline, mainly due to
tourist-accommodation facilities.
Fig.2 - SPA Lago di Mergozzo and Montorfano boundaries. The symbol marked trapping sites with fish-traps
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5
2.2 SCI IT1140001 Fondo Toce
This site (Fig. 3) include the last stretch of the Toce River, from the confluence with the Strona River to
its mouth with the Maggiore Lake. The area is mainly occupied by man-made environment, with crops,
greenhouses and tourist activities. The largest natural element is a vast area of reeds, mainly
composed by Phragmites australis with submerged and floating vegetations. This habitat has
considerable importance as resting place for migratory birds (about 190 overall species), and as
spawning or migratory site for many fishes (about 30 species, 7 of them included in the Habitat
Directive).
Fig.3 – SCI Fondo Toce boundaries. : trapping sites with fish-traps; : tansect with electro-fishing.
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6
2.3 SPA IT1140017 Fiume Toce
The Toce River (84 km) is the main stream of the Ossola Valley (Fig.4). The human presence is mainly
restricted around towns along the valley, particularly between the town of Fondotoce, at the confluence
of the lake, and Domodossola, located in the most upstream area of the SPA. The area of interest is
mostly natural, with flood plains well vegetated with typical peri-fluvial vegetation. Limited areas are
destined to agricultural productions, and along the river there are some industrial plants. The SPA
hosted 70 bird nesting species of about 150 reported, 7 included in the All. I of the Bird Directive. The
river hosts a significant fish population, with many species included in the All. II of the Habitat Directive:
Lethenteron zanandreai, Barbus caninus, Telestes muticellus, Salmo marmoratus, Cottus gobio.
Crevoladossola
Mizzoccola
Beura – 6 Arcate
Prata Vogogna
Pieve Vergonte
Gravellona Toce
Fig.4 - SPA Fiume Toce boundaries. Places in which removal of brown trout took place with electro-fishing are
written in yellow.
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7
3 EXECUTION
The Action started in time, as scheduled.
Sampling was organized in order to achieve the best results as possible, according to the different
characteristics of the sites (Fig. 5).
Among sites, a particular attention was addressed to the Fondotoce channel, which connects Lake
Maggiore to Lake Mergozzo. In this water body, multiple control actions were done by using
electrofishing and trap nets (Fig. 5A). Trap nets have been placed for a minimum of 4 days each site
and marked by a numerated float (Fig. 5B), while electrofishing has been conducted by using a built-in-
frame EL64GII (Scubla Acquaculture, 7,000 W, 600 V, DC current) set up with a copper cathode (width
2.5 cm, length 300 cm) and steel ring anode (thickness 0.8 cm, diameter 50 cm). Electrofishing was
conducted mainly by a boat, although in some occasion was also done near the shores especially in
Toce River (Fig. 5D).
A) B)
C) D)
Fig. 5. – A): Fondotoce channel (traps setting), B): Fondotoce channel (traps floaters), C): Lake Mergozzo, D): Toce
River (Mizzoccola)
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4 RESULTS
Places, dates and biomasses of alien invasive fish and crayfish species removed are indicated in Tab. 1,
2 and 3.
In the Fondotoce channel, the Black bullhead (Fig. 6B) was the most abundant alien species captured,
and its abundance seems to decrease from the first to the last campaign. However, it is still present
with high numbers.
A) B)
Fig. 6 – A): trap net for crayfish; B): black bullhead (Ameiurus melas)
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Table 1 - List and biomass of alien species. G = gillnets; E = electro-fishing, T = fish trap
Date Place Method Species Biomass (g)
Ameiurus melas 23871
Gymnocephalus cernuus 39
Lepomis gibbosus 2316
09/02/2017 Fondotoce channel E
Micropterus salmoides 109
Rhodeus amarus 17
Rutilus rutilus 4520
Ameiurus melas 2731
Carassius sp. 5808
Lepomis gibbosus 977
14/06/2017 Fondotoce channel E Micropterus salmoides 145
Rutilus rutilus 103
Sander lucioperca 5
Silurus glanis 37
Ameiurus melas 1553
Lepomis gibbosus 165
30/06/2017 Fondotoce channel E Micropterus salmoides 2
Rutilus rutilus 30
Trachemys scripta 500
Ameiurus melas 4100
02/10/2017 Fondotoce channel T
Orconectes limosus 100
Ameiurus melas 700
16/10/2017 Fondotoce channel T
Lepomis gibbosus 51
Ameiurus melas 299
Carassius sp. 51
17/10/2017 Fondotoce channel T Lepomis gibbosus 64
Orconectes limosus 4
Rutilus rutilus 30
Ameiurus melas 19662
Lepomis gibbosus 12
23/10/2017 Fondotoce channel T
Orconectes limosus 156
Trachemys scripta 2680
TOTAL BIOMASS 70837
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10Other alien species (Fig. 8A) are not so abundant as expected in the channel. Surprisingly, no Wels
catfish (Silurus glanis) were captured in the channel while some allochthonous slider turtles (Fig. 7A)
has been found. Also only a few alien crayfish (Fig. 7B) were captured in the trap nets, indicating a low
density in this sampling year. The low water levels however, could have prevented the migration of large
fish within the channel; indeed, only small fishes have been captured overall.
Table 2 - List and biomass of alien species. G = gillnets; E = electro-fishing, T = fish trap
Date Place Method Species Biomass (g)
22/12/2016 Lake Mergozzo G Rutilus rutilus 6000
Ameiurus melas 60
21/09/2017 Lake Mergozzo T
Trachemys scripta 500
TOTAL BIOMASS 6560
A) B)
Fig. 7 – A): Alien slider turtles (Trachemys scripta); B): American crayfish (Orconectes limosus)
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11Table 3 - List and biomass of alien species. G = gillnets; E = electro-fishing, T = fish trap
Date Place Method Species Biomass (g)
10/03/2017 Toce River E Salmo trutta 189
Oncorhynchus mykiss 97
Toce River E Rutilus rutilus 16
04/04/2017
Salmo trutta 151
Sander lucioperca 598
26/05/2017 Toce River E Salmo trutta 191
08/06/2017 Toce River E Salmo trutta 976
20/06/2017 Toce River E Salmo trutta 8638
Lepomis gibbosus 40
27/06/2017 Toce River E
Salmo trutta 1757
TOTAL BIOMASS 12563
A) B)
Fig. 8 – A): from left to right: Bitterling (Rhodeus amarus), Pumpkinseed (Lepomis gibbosus), Crucian carp
(Carassius carassius), Roach (Rutilus rutilus); B): Salmo trutta,
Regarding Toce River, specimens of Salmo trutta (Fig. 8B) have been found in all the samplings,
although with low abundances, indicating probably an absence of self-sustaining population but a
presence determined by repopulation by local anglers.
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125 NEXT STEPS
A public tender had been done in order to buy trap nets and other specific gears to be used in Lake
Mergozzo and Fondotoce channel. Gears will be delivered within the end of April, and will be used in the
new spring campaign starting (late April-June).
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